Animation fade to black?
Fade-to-black can be achieved in Blender if you feel like third-party video-editing software is not optimal, or the most succinct.


Assemble your image sequence/movie file into the Sequencer.
Scrub to a part in the timeline where you'd like to begin fading to black.

Goto to Sequencer menu, click Add -> Effect Strip -> Color.  (It defaults to Black, but you can make it any color).  Note this strip should be on top of your image sequence/movie file.

Select this color strip, and hit N to examine its properties over on the right.
Find the Opacity settings just in the Edit Strip section.
Scrub to the beginning of this Color strip.
Set the opacity to 0.  With the cursor over top of the slider, hit I to keyframe it.
Scrub to the end of the Color strip.
Change the opacity, this time to 1.0, and with the cursor in the slider field, hit I.  The color's opacity is now interpolated over the duration of the strip.




You can also fine-tune the interpolation like any keyframe by opening this strip in the F-Curve editor.  Happy editing!